Battery technology changes are on the way as vehicle electrical demands increase

Vehicle electrical systems are expanding and evolving to support a wider array of power-hungry technology, and to help enable new types of hybrid and electric vehicles.

Cars are brimming with new technologies, including advanced driver assistance systems (ADAS), cameras and sensors, semi-autonomous driving solutions, and others, that are putting more strain on batteries and electrical systems. While full electric vehicles present some installation and safety challenges for installers when it comes to battery and electrical systems, big changes are underway for conventional vehicles and hybrids as well.

A new vehicle may have as many as 150 electric motors and other features. There is a greater array of drivetrain components that are switching from mechanical to electric power, in addition to hybrid-drive parts and a need for more computing power in the vehicle for Internet connectivity, and vehicle-to-vehicle and vehicle-to-infrastructure applications.

“The introduction of these types of systems will continue through the end of the decade and the impact will only increase with even more powerful features like active safety and great powertrain electrification,” says Craig Rigby, advanced market and technology strategist at Johnson Controls Power solutions.

Automakers are turning to new battery technologies, in addition to higher-voltage systems, to power all of these innovations. More voltage also gives vehicle designers more options for increasing engine output and efficiency.

“There is really a push to manufacturer batteries that are stronger, have more capacity, and have more reserve capacity to supply all of the electronics in the vehicle,” says Joel Rozon, vice president of Trans-Canada Energies Distribution (TCED), a family owned importer/WD that is one of Canada’s leading battery and renewable energy distributors. The company has partnered with Shell to resurrect the Shell Battery product line in North America. “The biggest challenge is that there is only so much energy that you can put into a 13-inch container.”

According to IDTechEx, increased electrification in conventional vehicles will be further boosted by the use of torque assist systems and other energy harvesting methods, such as energy harvesting shock absorbers, active suspension, and photovoltaics. That means more power will need to be stored on those vehicles.

With these new systems will come a host of new parts and components, more SKUs, and a greater need for knowledge by distributors and at the parts counter when it comes to repairing or replacing electrical components and batteries.

With ADAS, for example, the new loads these systems present are pushing the capacity of existing 12-volt systems, and the electrical loads are peaky and unpredictable, Rigby says. “Today's power supply system is typically designed to handled predictable, switched loads with relatively small transients,” he adds. “ADAS systems are different. The reliability requirements for these systems are very high and that is causing a rethinking of the electrical system, including implementation of two or more batteries to provide redundancy.”

Sophisticated batteries

Batteries are increasingly sophisticated, so much so that removing or replacing a battery now requires a greater degree of knowledge. There are usually reset codes required so that the systems in the car know that the battery has been replaced. Not following proper procedures can affect vehicle performance.

“The programs in the vehicle are more complex, so as you pull out a battery it’s important to follow procedures,” Rozon says. “If you don’t do it properly or take measures to save these programs, such as plugging into the computer port or connecting voltage to the battery cables, you lose those settings. You might even have to have the vehicle towed out of the repair shop to the dealer just to get it reprogrammed, which is costly.”

Distributors and countermen should provide education to their customers and installers about just how much more complicated battery replacement has become. In fact, a Battery Council International survey found that half of consumers request assistance with battery installation. That’s because replacing a battery is no longer as simple as remembering which wire is the positive one.

“As these vehicles are being serviced it is important to replace the battery with the same technology in order to ensure proper function of the fuel-savings technology,” Rigby says. “Most of the start-stop vehicles on the market have some type of battery monitor so there is a little increase in complexity for replacement of that battery. As we start seeing more introduction of lithium-ion, the information related to service and replacement of these batteries will be defined by the individual automakers specific to their vehicles and systems.”

Batteries are also installed in more locations in the vehicle. According to Rozon, there are 27 different locations where a battery may be installed, including under the hood, under a rear seat, in the trunk and other areas. “Installers have to stay more educated about how the vehicle is built and the work that has to be done to access the battery,” he says. “You may need to take off a fender to get to a fuse box or battery, and reassemble that properly. The cost of installing batteries is going to go up as well because of the increased labor.”

Start-stop technology

As automakers work to meet increasingly stringent fuel economy and emissions standards, many have turned to start-stop technology, which cuts the engine when the car is stopped and restarts it once the driver takes his foot off the brake.

Over the next several years, more and more vehicles will include start-stop, which will reduce the amount of time the cars run while idling in order to improve fuel economy. According to Johnson Controls, the market for start-stop batteries is expected to rise to 56 million by 2020, and 85 percent of new vehicles in Europe and 40 percent of new vehicles in the U.S. will include the technology. Ford has estimated that some 70 percent of its vehicles will eventually offer it, and all Buicks will have it by model year 2018.

While it saves fuel, start-stop puts more strain on the battery because it has to cycle many more times per day. Most companies also advise that batteries in start-stop vehicles be changed by a professional to ensure the system keeps working correctly.

These systems also require better batteries, and many automakers are using enhanced flooded batteries (EFB), absorbent glass mat batteries (AGM), or 12-volt lithium-ion batteries.

Demand for AGM batteries has increased over time. AGM batteries are a type of advanced lead-acid batteries with better cycling performance – making them a better fit for start-stop vehicles.

Unlike flooded lead-acid batteries, AGM batteries include a glass mat separator that maintains electrolyte around the positive plate, which extends the battery life. The batteries are more resistant to vibration and deliver improved cycle life and higher energy.

“You can compress the battery and fit more electrical lead plates inside to make it more powerful,” Rozon says. “We will see more AGM batteries in vehicles, particularly those with start-stop technology.”

AGM batteries are also less effected by heat. Flooded batteries lose electrolyte and can burn up their lead plates when they get too hot. “With AGM, there is no liquid inside, so you don’t lose electrolyte. The lead plates don’t break off because they are more resistant to vibration, and they typically have more reserve capacity,” Rozon says.

Are 48-volt batteries the future?

The big news in conventional and hybrid vehicles may be the adoption of 48-volt battery systems. Generating more power allows for the adoption of torque assist systems to help reduce fuel consumption and emissions in hybrids. In some cases, torque assist may be able to keep a vehicle operating at cruising speed without the gas engine being engaged.

Such systems could reduce engine size and require fewer gears. These “mild hybrid” vehicles using 48-volt systems could provide as much as 70 percent of the benefits of a full hybrid (which require large, expensive battery packs) at roughly a third of the cost. According to Delphi, 48-volt mild hybrids could cut emissions by 15 to 20 percent.

There are different types of battery solutions for mild hybrids in different markets. In Japan, the market is spit between strong hybrids (with 100-volt systems) and mild solutions for light vehicles that use 12-volt batteries. Europe and China have embraced 48-volt systems because they provide a cost-effective way of improving fuel economy.

“In addition, as ADAS systems move closer to fully autonomous vehicles in the next decade, 48-volt systems may be a key enabler to managing the amount of electrical power required to handle all the chassis and connectivity functionality,” Rigby says. “48-volt systems are considered low-voltage so the safety-related requirements for assembly and service of the components are less complicated and less costly than high-voltage systems found in hybrid electric vehicles.”

Johnson Controls has invested heavily in 48-volt technology, and offers a lithium-ion battery for micro-hybrid/mild hybrid applications.

Audi already has a 48-volt system in its SQ7 SUV. The vehicle (which is not actually a hybrid) uses the 48-volt system to run an electrically driven turbine to force extra air into the engine, which the company says provides faster performance than a turbocharger. It also powers the self-leveling suspension system. The company is using a lithium-ion 48-volt battery, while a DC/DC converter is used to integrate the 12-volt system.

The Advanced Diesel Electric Powertrain (ADEPT) consortium in the UK is testing an experimental Ford Focus, which uses a 48-volt system to power a number of components on the vehicle. The CPT SpeedStart is a different advanced motor-generator system for 48-volt mild hybrids that provides up to two million stop-starts, torque assist, and better energy harvesting from regenerative braking than is possible with a 12v stop-start system.

Earlier this year, Delphi Automotive announced a 48-volt vehicle solution that is already under consideration by two automakers. According to the company, the system can lower emissions by more than 10 percent.

"This is not only a significant step forward with reinventing the electrical architecture for dual voltage capability, it is also a triumph of software," said Jeff Owens, Delphi's chief technology officer. "This intelligent approach to vehicle power, wiring and data management will not only improve fuel efficiency, but will also enable a world-class driving experience while providing additional power for active safety systems and increased connectivity in the car."

Hitachi also announced a new 48-volt lithium-ion battery pack for mild hybrids, and planned to begin mass producing the solution by 2018.

In hybrid vehicles, which generate power during braking, 48-volt systems can provide better energy handling. The Delphi system uses an electric turbocharger to improve vehicle launch when the engine is restarted. The additional battery provides four times more power to provide faster processing and lower the burden on the engine.

“Some vehicle manufacturers could be faced with hefty annual emissions fines if CO2 emissions requirements are not met,” Owens said. “We can design a cost-effective 48-volt system. That’s especially attractive when you consider the cost of lithium-ion batteries, the lack of range, charging infrastructure and customer demand.”

The 48-volt systems also can improve start-stop performance. In the short term, most vehicles that shift to 48-volt will use both 12-volt and 48-volt systems. Typically, a 12-volt lead acid battery would handle traditional loads like lighting, ignition, audio/entertainment, etc., while the 48-volt battery (often lithium-ion) would support regenerative braking, active chassis systems, AC compressors and other systems on a separate network.

How quickly 48-volt systems are adopted remains to be seen, but distributors, retailers, and installers clearly need to stay on top of their education efforts as new types of batteries (AGM, lithium-ion), higher voltage batteries and more complex electrical components enter the market.

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